Journal of Welding and Joining

9: J Weld Join. 2015;33(2):8-13. Published online April 30, 2015.
DOI: https://doi.org/10.5781/JWJ.2015.33.2.8; Evaluation of mechanical properties on friction stir lap jointed Al6061/HT590 alloys; Eun-Hye Kim^*, Kwang-Jin Lee^**, Kuk-Hyun Song^*; Corresponding author: Kuk-Hyun Song ,Email: skhyun7@kitech.re.kr

Abstract: This study was carried out to evaluate mechanical properties of the jointed Al6061/HT590 alloys by friction stir welding (FSW). FSW was conducted under the conditions with tool rotating speed of 500 RPM and traveling speed of 300 mm/min., where Ar gas was introduced to prevent the materials from corrosion during the welding process. Electron back-scattering diffraction (EBSD) was used to characterize micro-structures such as grain size, misorientation angle and crystal orientation. Evolution of intermetallic compounds in Al6061 during the process were examined in terms of morphology, size and aspect ratio at three distinct zones Al base material, heat affected zone and stir zone, where transmission electron micro-scope (TEM) was used. It was revealed that FSW gave rise to refinement of grains as well as growth of intermetallic compounds in Al6061. The morphological changes of intermetallic compounds exerted an influence on mechanical properties, resulting in occurrence of fracture in the part of the base material instead of the jointed parts (heat affected zone and stir zone). This study systematically evaluated the microstructural evolutions during the FSW for joining Al6061 with HT590 and their effect on mechanical properties

Keywords :Friction stir lap joint, Al6061/HT590, Microstructure, Electron back-scattering diffraction (EBSD), Transmission electron microscope (TEM), Mechanical properties